U.S. patent number 6,006,913 [Application Number 08/662,436] was granted by the patent office on 1999-12-28 for packaging.
This patent grant is currently assigned to BP Chemicals PlasTec GmbH, PCD Polymere Gesellschaft mbH. Invention is credited to Manfred Grunberger, Harald Hammer, Robert Linz, Henning Ludemann, Jurgen Schnabele, Anton Wolfsberger.
United States Patent |
6,006,913 |
Ludemann , et al. |
December 28, 1999 |
**Please see images for:
( Certificate of Correction ) ** |
Packaging
Abstract
A packaging for goods, such as, for example, tablets, capsules
or the like, is suggested which is simple to produce and can be
handled without problem, comprising a packaging lower part and a
cover film, wherein the goods are arranged individually between the
packaging lower part and the cover film and enclosed by them,
wherein the cover film comprises a pull-off layer and a
push-through layer which are designed such that first of all the
pull-off layer can be detached from the packaging in sections and
the goods then removed individually by being pushed through the
push-through layer, wherein the pull-off layer is peelably
connected to the push-through layer, wherein the push-through layer
is connected to the lower part by means of a sealing layer and
wherein the push-through layer is produced on a polymer basis.
Inventors: |
Ludemann; Henning (Memmingen,
DE), Linz; Robert (Dietenheim, DE),
Schnabele; Jurgen (Bernried, DE), Grunberger;
Manfred (Traun, AT), Wolfsberger; Anton
(Engerwitzdorf, AT), Hammer; Harald (Pasching,
AT) |
Assignee: |
BP Chemicals PlasTec GmbH
(Dietenheim, DE)
PCD Polymere Gesellschaft mbH (DE)
|
Family
ID: |
7790763 |
Appl.
No.: |
08/662,436 |
Filed: |
June 10, 1996 |
Foreign Application Priority Data
|
|
|
|
|
Apr 9, 1996 [DE] |
|
|
196 13 959 |
|
Current U.S.
Class: |
206/531; 206/528;
428/323; 428/329; 428/330; 206/532; 206/828; 220/526; 428/326;
428/328; 428/35.2; 428/35.7; 525/240; 428/331; 428/327; 220/359.3;
206/539 |
Current CPC
Class: |
A61J
1/035 (20130101); C09J 123/04 (20130101); C09J
123/142 (20130101); B65D 75/327 (20130101); C09J
123/04 (20130101); C09J 123/142 (20130101); Y10T
428/256 (20150115); B65D 2575/3245 (20130101); C08L
2205/02 (20130101); Y10S 206/828 (20130101); Y10T
428/1334 (20150115); Y10T 428/259 (20150115); Y10T
428/253 (20150115); Y10T 428/257 (20150115); Y10T
428/25 (20150115); Y10T 428/1352 (20150115); Y10T
428/258 (20150115); Y10T 428/254 (20150115); C08L
2666/04 (20130101); C08L 2666/04 (20130101); C08L
2666/04 (20130101) |
Current International
Class: |
A61J
1/00 (20060101); C09J 123/00 (20060101); C09J
123/04 (20060101); A61J 1/03 (20060101); B65D
75/28 (20060101); B65D 75/34 (20060101); C09J
123/14 (20060101); B65D 083/04 () |
Field of
Search: |
;206/531,532,539,528,828
;428/35.7,35.2,323,326,328,329,330,331 ;220/359.3,526 ;525/240 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Teskin; Fred
Attorney, Agent or Firm: Leydig, Voit & Mayer
Claims
We claim:
1. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part;
a seal/peel layer covering said push-through layer;
a peelable pull-off layer covering said seal/peal layer, said
seal/peal layer thereby peelably connecting said pull-off layer to
said push-through layer whereby said pull-off layer may be peeled
away from said push-through layer,
wherein said seal/peel layer comprises a mixture of two polymeric
components I and II, wherein said component I is selected from the
group consisting of propylene homopolymers, copolymers of ethylene
and propylene; copolymers of ethylene and butylene; copolymers of
propylene and butylene; copolymers of ethylene and a different
.alpha.-olefin with 5 to 10 carbon atoms; copolymers of propylene
and a different .alpha.-olefin with 5 to 10 carbon atoms;
terpolymers of ethylene and propylene and butylene; terpolymers of
ethylene and propylene and a different .alpha.-olefin with 5 to 10
carbon atoms; and mixtures of two or more of the specified
homopolymers, copolymers and terpolymers or a blend of two or more
of the specified homopolymers, copolymers and terpolymers,
optionally mixed with one or more of the specified homopolymers,
copolymers and terpolymers, wherein said component II is a polymer
incompatible with said component I.
2. A packaging according to claim 1, wherein said component II is
selected from the group consisting of high density polyethylenes,
medium density polyethylenes, low density polyethylenes, linear low
density polyethylenes, very low density polyethylenes, and ultra
low density polyethylenes.
3. A packaging according to claim 2, wherein said component II is
produced using a metallocene catalyst.
4. A packaging according to claim 1, wherein said lower part
comprises plural discrete subparts, each subpart individually
containing a product such that product in any one subpart is
continued in said packaging separately from product in any other
subpart, said pull-off layer being provided in discrete sections,
each one of said subparts having a corresponding section, whereby a
section of said pull-off layer may be peeled away over one subpart
and the product contained therein may be pushed through the
remaining layers of said covering film without releasing product
contained in other subparts.
5. Packaging as defined in claim 1, wherein said lower part is
produced from a plastic material.
6. Packaging as defined in claim 5, wherein said plastic material
is essentially the same as the material of said push-through
layer.
7. Packaging as defined in claim 1, wherein the lower part has a
sealing layer on a surface thereof to be connected with the
push-through layer.
8. Packaging as defined in claim 1, wherein said sealing layer is
produced by using a polyolefin selected from the group consisting
of polypropylene random copolymers, terpolymers, ionomers, ethylene
copolymers, acid-modified polyolefins, grafted polyolefins
containing styrene and ethylene butylene blocks, polyolefins
produced using a metallocene catalyst, random heterophase
copolymers, highly amorphous polypropylenes, and mixtures of two or
more of the aforementioned polymers.
9. Packaging as defined in claim 1, wherein said sealing layer
comprises a material selected from the group consisting of ethylene
butyl acrylate, ethylenevinyl acetate, ethylene ethyl acetate,
ethylene acrylic acid, and ethylene maleic anhydride
copolymers.
10. Packaging as defined in claim 1, wherein said sealing layer
comprises a material selected from the group consisting of linear
low, very low and ultra low density polyethylene copolymers.
11. Packaging as defined in claim 1, wherein said sealing layer
comprises a terpolymer which is formed from propylene, ethylene and
an additional .alpha.olefin.
12. Packaging according to claim 11, wherein said .alpha.-olefin is
selected from the group consisting of butene, hexene and
octene.
13. Packaging as defined in claim 11, wherein the terpolymer is
produced using a metallocene catalyst.
14. Packaging as defined in claim 1, wherein said sealing layer is
selected from the group consisting of random copolymers and random
heterophase copolymers of propylene with ethylene, butene, hexene
and/or octene as comonomer.
15. Packaging as defined in claim 14, wherein the material of the
sealing layer is grafted with maleic anhydride.
16. Packaging as defined in claim 14, wherein the propylene random
copolymers and the random heterophase copolymers are produced using
a metallocene catalyst.
17. Packaging as defined in claim 7, wherein the sealing layer is
coextruded with the lower part.
18. Packaging as defined in claim 1, wherein the sealing layer is
coextruded with the push-through layer.
19. Packaging as defined in claim 7 wherein the sealing layer is
applied to the lower part as a lacquer coating.
20. Packaging as defined in claim 1, wherein the push-through layer
comprises a polymer selected from the group consisting of PVC,
polystyrene, styrene copolymerisates, polyester, and
polyolefins.
21. Packaging as defined in claim 20, wherein the push-through
layer comprises a polymer matrix containing a particulate filler
selected and contained in such constituent amounts in the matrix
that the puncture resistance of the push-through layer is reduced
to below a limit of 450 N/mm, as measured on a film 150 .mu.m
thick.
22. Packaging as defined in claim 20, wherein the polyolefin of the
push-through layer comprises polypropylene.
23. Packaging as defined in claim 22, wherein said polypropylene is
produced using a metallocene catalyst.
24. Packaging as defined in claim 23, wherein the polypropylene of
the push-through layer comprises high crystalline
polypropylene.
25. Packaging as defined in claim 1, wherein the resistance to
further tearing of the push-through layer is reduced to below a
limit of 30 N.
26. Packaging as defined in claim 1, wherein the value of the
puncture resistance of the push-through layer is approximately 50
to approximately 200 N/mm.
27. Packaging as defined in claim 1, wherein the resistance to
further tearing is approximately 3 to 4 N.
28. Packaging as defined in claim 21, wherein said filler is
selected from the group consisting of halogenated hydrocarbon
polymers, polyether sulfones, cellulose, wood pulp, and duroplastic
materials.
29. Packaging as defined in claim 21, wherein said filler is
selected from the group consisting of SiO.sub.2, silicates,
titanates, TiO.sub.2, aluminum oxide, kaolin, calcium carbonates,
magnesites, MgO, iron oxides, silicon carbide, silicon nitride, and
barium sulfate.
30. Packaging as defined in claim 21, wherein the filler content in
the polymer matrix is approximately 5% by weight to approximately
60% by weight.
31. Packaging according to claim 30, wherein said filler content in
the polymer matrix is approximately 10% by weight to approximately
55% by weight.
32. Packaging as defined in claim 20, wherein the particle size of
the filler particles, measured over their greatest extension, is on
average approximately 5 .mu.m to 100 .mu.m.
33. Packaging as defined in claim 1, wherein the push-through layer
comprises a polymer phase containing a polyolefin (A) and a
hydrocarbon resin component (B) dissolved therein, wherein the
hydrocarbon resin component (B) is different from the polyolefin
(A), and comprises cyclic side groups on the polymer chain and is
contained in the push-through layer with a proportion of at least
approximately 3% by weight of the total mass, wherein the
proportion of the hydrocarbon resin component (B) is at the most
approximately 30% by weight, wherein that the hydrocarbon resin
component (B) is an amorphous polymer, and wherein a filler is
contained in the push-through layer with a proportion of 0 to 35%
by weight of the total mass, wherein the puncture resistance is
reduced to below a limit of 450 N/mm.
34. Packaging as defined in claim 33, wherein the proportion of
hydrocarbon resin (B) is at most approximately 25% by weight.
35. Packaging according to claim 34, wherein said filler is
contained in the push-through layer in an amount of at most
approximately 30% by weight.
36. Packaging according to claim 35, wherein said filler is
contained in the push-through layer in an amount of at most
approximately 25% by weight.
37. Packaging as defined in claim 1, wherein characterized in that
the peel/seal layer is designed as a lacquer coating or coextruded
together with the pull-off layer or the push-through layer.
38. Packaging as defined in claim 1, wherein the seal/peel layer is
designed as an adhesive layer.
39. Packaging as defined in claim 1, wherein the seal/peel layer
comprises a mixture of:
a1) 30 to 80% by weight of a polymer mixture, consisting of
a1.1) 60 to 98% by weight of a crystalline copolymer consisting of
propylene with ethylene and/or an .alpha.-olefin of the formula
CH.sub.2 --CHR, wherein R is a linear or branched alkyl radical
with 2 to 8 carbon atoms, containing 85 to 99.5% by weight of
propylene, and
a1.2) 2 to 40% by weight of an elastic copolymer consisting of
ethylene and propylene and/or an .alpha.-olefin of the formula
CH.sub.2 --CHR, containing20 to 70% by weight of ethylene or
a2) 30 to 80% by weight of a highly amoiphous polypropylene with a
crystalline polypropylene proportion of up to 10% by weigh with a
melting enthalpy of at the most 40 J/g and a melt-flow index of
between 0.1 and 100 g/10 min, wherein the polypropylene can be a
homopolymer of the propylene or a copolymer of the propylene with
one or more .alpha.-olefins and a propylene proportion of at least
80 mol %, and
a3) 70 to 20% by weight of an ethylene polymerisate.
40. Packaging as defined in claim 1, wherein the seal/peel layer is
sealable at temperatures of up to 180.degree. C.
41. Packaging as defined in claim 1, wherein the pull-off layer is
produced from a thermally stable material selected from the group
consisting of unfilled and filled propylene homopolymers, high
crystalline polypropylenes, paper, and oriented, filled or unfilled
polyamide, polyester, or polypropylene polymers.
42. Packaging as defined in claim 1, wherein said covering film
includes a heat-resistant protective layer.
43. Packaging as defined in claim 1, wherein the lower part is
sealed to the cover film along a sealing seam around the individual
goods so as to be essentially moisture proof and essentially
oxygen-tight.
44. Packaging as defined in claim 43, wherein the peeling force is
.ltoreq.5 N, with a peeling front of 22 mm in width.
45. Packaging as defined in claim 44, wherein the peeling force is
.ltoreq.3 N with a peeling front of 22 mm in width.
46. Packaging as defined in claim 45, wherein the peeling force is
.ltoreq.2N with a peeling front of 22 mm in width.
47. Packaging as defined in claim 4, wherein the cover film has a
tear-initiation area designed such that first of all the cover film
is adapted to be grasped as a whole but during the removal of the
cover film along predetermined contours the pull-off layer of the
cover film is separated from the push-through layer and the
pull-off layer is adapted to be detached further on its own.
48. Packaging as defined in claim 47, characterized in that the
contours of the tear-initiation area comprise an interrupted line,
a saw tooth or wave shape or an angular shape directed contrary to
the pull-off direction.
49. Packaging as defined in claim 47, characterized in that the
tear-initiation area comprises a grip tab not sealed to the lower
part and, where applicable, connected thereto via sealing points
having a small area to ensure the plane state.
50. Packaging as defined in claim 1, characterized in that in the
case of the cover film the pull-off layer is connected to the
seal/peel layer and the push-through layer by means of a
thermolaminating process.
51. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part;
said packaging including a peelable pull-off layer covering said
push-through layer, whereby said pull-off layer may be peeled away
from said push-through layer, wherein said sealing layer comprises
a polymer selected from the group consisting of polypropylene
random copolymers, terpolymers, ionomers, ethylene copolymers,
acid-modified polyolefins, grafted polyolefins containing styrene
and ethylene butylene blocks, polyolefins produced using a
metallocene catalyst, random heterophase copolymers, highly
amorphous polypropylenes, and mixtures of two or more of the
aforementioned polymers,
wherein said lower part comprises plural discrete subparts, each
subpart individually containing a product such that product in any
one subpart is continued in said packaging separately from product
in any other subpart, said pull-off layer being provided in
discrete sections, each to one of said subparts having a
corresponding section, whereby a section of said pull-off layer may
be peeled away over one subpart and the product contained therein
may be pushed through the remaining layers of said covering film
without releasing product contained in other subparts,
wherein the lower part has a sealing layer on a surface thereof to
be connected with the push-through layer,
wherein said sealing layer comprises a terpolymer which is formed
from propylene, ethylene and an additional .alpha.-olefin.
52. Packaging according to claim 51, wherein said .alpha.-olefin is
selected from the group consisting of butene, hexene and
octene.
53. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part; said packaging including a peelable
pull-off layer covering said push-through layer, whereby said
pull-off layer may be peeled away from said push-through layer,
wherein said sealing layer comprises a polymer selected from the
group consisting of polypropylene random copolymers, terpolymers,
ionomers, ethylene copolymers, acid-modified polyolefins, grafted
polyolefins containing styrene and ethylene butylene blocks,
polyolefins produced using a metallocene catalyst, random
heterophase copolymers, highly amorphous polypropylenes, and
mixtures of two or more of the aforementioned polymers,
wherein said sealing layer is selected from the group consisting of
random copolymers and random heterophase copolymers of propylene
with ethylene, butene, hexene and/or octene as comonomer.
54. Packaging as defined in claim 53, wherein the material of said
sealing layer is grafted with maleic anhydride.
55. Packaging as defined in claim 53, wherein the propylene random
copolymers and the random heterophase copolymers are produced using
a metallocene catalyst.
56. Packaging as defined in claim 51, wherein the terpolymer is
produced using a metallocene catalyst.
57. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part; said packaging including a peelable
pull-off layer covering said push-through layer, whereby said
pull-off layer may be peeled away from said push-through layer,
wherein said sealing layer comprises a polymer selected from the
group consisting of polypropylene random copolymers, terpolymers,
ionomers, ethylene copolymers, acid-modified polyolefins, grafted
polyolefins containing styrene and ethylene butylene blocks,
polyolefins produced using a metallocene catalyst, random
heterophase copolymers, highly amorphous polypropylenes, and
mixtures of two or more of the aforementioned polymers, wherein the
push-through layer comprises a polymer selected from the group
consisting of PVC, polystyrene, styrene copolymerisates, polyester,
and polyolefins, wherein the push-through layer comprises a polymer
matrix containing a particulate filler selected and contained in
such constituent amounts in the matrix that the puncture resistance
of the push-through layer is reduced to below a limit of 450 N/mm,
as measured on a film 150 .mu.m thick.
58. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part; said packaging including a peelable
pull-off layer covering said push-through layer, whereby said
pull-off layer may be peeled away from said push-through layer,
wherein said sealing layer comprises a polymer selected from the
group consisting of polypropylene random copolymers, terpolymers,
ionomers, ethylene copolymers, acid-modified polyolefins, grafted
polyolefins containing styrene and ethylene butylene blocks,
polyolefins produced using a metallocene catalyst, random
heterophase copolymers, highly amorphous polypropylenes, and
mixtures of two or more of the aforementioned polymers,
wherein the push-through layer comprises a polymer selected from
the group consisting of PVC, polystyrene, styrene copolymerisates,
polyester, and polyolefins, wherein the polyolefin of the
push-through layer comprises polypropylene.
59. Packaging as defined in claim 58, wherein the polypropylene of
the push-through layer comprises high crystalline
polypropylene.
60. Packaging as defined in claim 57, wherein said filler is
selected from the group consisting of halogenated hydrocarbon
polymers, polyether sulfones, cellulose, wood pulp, and duroplastic
materials.
61. Packaging as defined in claim 57, wherein said filler is
selected from the group consisting of SiO.sub.2, silicates,
titanates, TiO.sub.2, aluminum oxide, kaolin, calcium carbonates,
magnesites, MgO, iron oxides, silicon carbide, silicon nitride, and
barium sulfate.
62. Packaging as defined in claim 57, wherein the filler content in
the polymer matrix is approximately 5% by weight to approximately
60% by weight.
63. Packaging according to claim 62, wherein said filler content in
the polymer matrix is approximately 10% by weight to approximately
55% by weight.
64. Packaging as defined in claim 57, wherein the particle size of
the filler particles, measured over their greatest extension, is on
average approximately 5 .mu.m to 100 .mu.m.
65. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part;
said packaging including a peelable pull-off layer covering said
push-through layer, whereby said pull-off layer may be peeled away
from said push-through layer, w0herein said sealing layer comprises
a polymer selected from the group consisting of polypropylene
random copolymers, terpolymers, ionomers, ethylene copolymers,
acid-modified polyolefins, grafted polyolefins containing styrene
and ethylene butylene blocks, polyolefins produced using a
metallocene catalyst, random heterophase copolymers, highly
amorphous polypropylenes, and mixtures of two or more of the
aforementioned polymers,
wherein the push-through layer comprises a polymer phase containing
a polyolefin (A) and a hydrocarbon resin component (B) dissolved
therein, wherein the hydrocarbon resin component (B) is different
from the polyolefin (A), and comprises cyclic side groups on the
polymer chain and is contained in the push-through layer with a
proportion of at least approximately 3% by weight of the total
mass, wherein that the proportion of the hydrocarbon resin
component (B) is at the most approximately 30% by weight, wherein
the hydrocarbon resin component (B) is an amorphous polymer, and
wherein a filler is contained in the push-through layer with a
proportion of 0 to 35% by weight of the total mass, wherein the
puncture resistance is reduced to below a limit of 450 N/mm.
66. Packaging as defined in claim 65, wherein the proportion of
hydrocarbon resin (B) is at most approximately 25% by weight.
67. Packaging according to claim 66, wherein said filler is
contained in the push-through layer in an amount of at most
approximately 30% by weight.
68. Packaging according to claim 67, wherein said filler is
contained in the push-through layer in an amount of at most
approximately 25% by weight.
69. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part; said packaging including a peelable
pull-off layer covering said push-through layer, whereby said
pull-off layer may be peeled away from said push-through layer,
wherein said sealing layer comprises a polymer selected from the
group consisting of polypropylene random copolymers, terpolymers,
ionomers, ethylene copolymers, acid-modified polyolefins, grafted
polyolefins containing styrene and ethylene butylene blocks,
polyolefins produced using a metallocene catalyst, random
heterophase copolymers, highly amorphous polypropylenes, and
mixtures of two or more of the aforementioned polymers, wherein the
peelable connection is formed by means of a seal/peel layer,
wherein said seal/peel layer comprises a mixture of two polymeric
components I and II, wherein said component I is selected from the
group consisting of propylene homopolymers, copolymers of ethylene
and propylene; copolymers of ethylene and butylene; copolymers of
propylene and butylene, copolymers of ethylene and a different
.alpha.-olefin with 5 to 10 carbon atoms, copolymers of propylene
and a different .alpha.olefin with 5 to 10 carbon atoms;
terpolymers of ethylene and propylene and butylene, terpolymers of
ethylene and propylene and a different .alpha.-olefin with 5 to 10
carbon atoms; and mixtures of two or more of the specified
homopolymers, copolymers and terpolymers or a blend of two or more
of the specified homopolymers, copolymers and terpolymers, wherein
said component II is a polymer incompatible with said Component
I.
70. Packaging as defined in claim 69, wherein said component II is
selected from the group consisting of high density polyethylenes,
medium density polyethylenes, low density polyethylenes, linear low
density polyethylenes, very low density polyethylenes, and ultra
low density polyethylene.
71. Packaging according to claim 70, wherein said component II is
provided using a metallocene catalyst.
72. A packaging comprising:
a product
a packaging lower part having a cavity defining a product holding
receptacle, said product being disposed within said receptacle;
and
a covering film covering said cavity thereby enclosing said product
in said packaging, said covering film comprising:
a sealing layer;
a push-through layer covered on a surface thereof by said
sealing
layer, said sealing layer thereby connecting said push-through
layer to said lower part;
said packaging including a peelable pull-off layer covering said
push-through layer, whereby said pull-off layer may be peeled away
from said push-through layer, wherein said sealing layer comprises
a polymer selected from the group consisting of polypropylene
random copolymers, terpolymers, ionomers, ethylene copolymers,
acid-modified polyolefins, grafted polyolefins containing styrene
and ethylene butylene blocks, polyolefins produced using a
metallocene catalyst, random heterophase copolymers, highly
amorphous polypropylenes, and mixtures of two or more of the
aforementioned polymers,
wherein the peelable connection is formed by means of a seal/peel
layer, wherein the seal/peel layer comprises a mixture of:
a1) 30 to 80% by weight of a polymer mixture, consisting of
a1.1) 60 to 98% by weight of a crystalline copolymer consisting of
propylene with ethylene and/or an .alpha.-olefin of the formula
CH.sub.2 --CHR, wherein R is a linear or branched alkyl radical
with 2 to 8 carbon atoms, containing 85 to 99.5% by weight of
propylene, and
a1.2) 2 to 40% by weight of an elastic copolymer consisting of
ethylene and propylene and/or an .alpha.-olefin of the formula
CH.sub.2 --CHR, containing 20 to 70% by weight of ethylene or
a2) 30 to 80% by weight of a highly amorphous polypropylene with a
crystalline polypropylene proportion of up to 10% by weight with a
melting enthalpy of at the most 40 J/g and a melt-flow index of
between 0.1 and 100 g/10 min, wherein the polypropylene can be a
homopolymer of the propylene or a copolymer of the propylene with
one or more .alpha.-olefins and a propylene proportion of at least
80 mol %, and
a3) 70 to 20% by weight of an ethylene polymerisate.
Description
TECHNICAL FIELD OF THE INVENTION
The invention relates to a packaging for goods, such as, for
example, tablets, capsules or the like, comprising a packaging
lower part and a cover film, wherein the goods are arranged
individually between the packaging lower part and the cover film
and are enclosed by them.
BACKGROUND OF THE INVENTION
In order to make the packaging child-proof, which is of
significance, in particular, in the case of the packaging for
pharmaceuticals, it has already been suggested that the cover film
be formed from a pull-off layer and a push-through layer which are
designed such that for removing the packaged goods, in particular
the tablets or the like, the pull-off layer is first of all to be
detached in sections, whereby the push-through layer (in the form
of an aluminum film or foil) of the cover film is exposed. This can
be pushed through once the pull-off layer has been detached, i.e.
the packaged goods can be removed by applying mechanical force to
the rear side of the packaging and by pressing the goods through
the push-through layer, which thereby tears.
The problem with the known packagings of this type is, however,
that the connection between the pull-off layer and the push-through
layer, on the one hand, and/or the connection of the cover film
with the packaging lower part is inadequate and so, in many cases,
the pull-off layer and the push-through layer are pulled off
together which means that the packaging is no longer child-proof
or, however, the removal of the pull-off layer proves to be very
difficult and so older patients, in particular, have difficulty in
removing the tablets from the packaging.
The problems are based, in particular, on the fact that with this
type of packaging a compromise had to be sought, with which, on the
one hand, the cover film adheres firmly enough to the packaging
lower part, with which, in addition, the pull-off layer is
connected to the push-through layer rigidly enough to prevent any
opening of the package without any previous removal of the pull-off
layer and, on the other hand, the removal of the pull-off layer
from the push-through layer must take place easily enough to ensure
a simple removal of tablets. In addition, the pull-off layer must
be detachable in sections so that during the desired removal of a
tablet from the packaging and the detachment of the associated
section of the pull-off layer further tearing and further removal
of the entire pull-off layer or larger portions thereof does not
result.
In the case of previously known packagings of the type described at
the outset, the pull-off layer is often produced from paper and the
push-through layer is an aluminum foil. In the case of different
packagings, the pull-off layer consists of a paper layer reinforced
with plastic and the push-through layer of an aluminum foil. In
order to facilitate opening, sections of the pull-off layer and
push-through layer are not then sealed to the packaging lower part
and so the combined layers consisting of pull-off layer and
push-through layer can be gripped together more easily. In order,
however, to avoid any unintentional opening, these sections which
are not sealed to the lower part are arranged in the interior of
the overall surface of the packaging and are not accessible until a
section comprising a single tablet has been broken out of the
packaging along perforation lines.
To remedy these problems, U.S. Pat. No. 4,537,312 proposes
providing the packaging lower part, which is provided with pockets
for accommodating the tablets, capsules, etc., with apertures
between the pockets and covering the packaging lower part from
above and from below with a plastic material and sealing this in
the edge region and in the region of the apertures. In order to
ensure a good abutment of the covering on the side of the pockets
of the lower part, it is then suggested to arrange suitable
apertures, through which the pockets can project, in this part of
the covering in the region of the pockets of the packaging lower
part.
This type of packaging is extremely complicated and still does not
eliminate the problem of the complicated handling and the partially
undesired opening of the individual pockets of the packaging lower
part during removal of the pull-off layer.
It is the object of the invention to propose a packaging which is
simple to produce in comparison with the known packagings of the
type described at the outset and eliminates the problems during
handling which are described in the above.
OBJECTS AND SUMMARY OF THE INVENTION
This object is accomplished in accordance with the invention, in a
packaging described at the outset, in that the pull-off layer is
peelably connected to the push-through layer, that the push-through
layer is connected to the lower part by means of a sealing layer,
and that the push-through layer is produced on a polymer basis.
With respect to the complex object specified above, the core of the
present invention is to be seen first of all in the fact that in
combination
the pull-off layer is peelably connected to the push-through layer,
wherein peelable connections such as those known per se can also be
used in this case,
the push-through layer is connected to the lower part by means of a
sealing layer which can likewise be known per se,
and, above all, the push-through layer is produced on a polymer
basis.
This group of measures allows an exact coordination of the
individual layers and their connections with one another which, in
the end, ensures a secure closure of the packaging, on the one
hand, and a reliable opening in the prescribed sequence of steps,
on the other hand.
FIG. 1 is a schematic cross sectional illustration of a packaging
in accordance with one embodiment of the invention.
FIG. 2 is a plan view of another embodiment of the packaging of the
invention.
FIG. 3 is a plan view of yet another embodiment of the packaging of
the invention.
DESCRIPTION OF THE INVENTION
The packaging lower part will preferably be a thermoformed
packaging lower part, recesses resulting in the film of the
packaging lower part due to the thermoforming process which can
accommodate the goods individually or in a predetermined quantity
or number.
With regard to the purity of type of the packaging often aimed for,
the packaging lower part is preferably produced from a plastic
material which is preferably produced from a plastic material
similar to the material of the push-through layer. Ideally, the
composition of the cover film as a whole and of the packaging lower
part is then at least similar and so the resources required for
reuse or recycling of the packaging and the waste which results
during the production of the packaging is simplified since a
separation of useful materials need no longer take place.
The sealing layer, which ensures a firm and permanent connection
between push-through layer and packaging lower part, can be applied
alternatively to the lower part or rather to its surface to be
connected to the push-through layer or, however, to the surface of
the push-through layer which is intended to be connected to the
lower part, or, however, to the corresponding surface of the lower
part as well as to the surface of the push-through layer which are
intended to be connected to one another.
The question of the use of one or two sealing layers or rather the
decision to apply the sealing layer on the side of the push-through
layer or on the side of the lower part is dependent on the polymer
materials used not only for the push-through layer but also for the
lower part, on the one hand, and, on the other hand, on the
required strength of the seal.
The material for forming the sealing layer is preferably produced
with the use of polyolefins having a low melting point, the
following polymers being recommended, in particular, as essential
components of the sealing layer:
Polypropylene random copolymers, terpolymers, ionomers, ethylene
copolymers, in particular ethylene butyl acrylate, ethylenevinyl
acetate, ethylene ethyl acetate, ethylene acrylic acid and ethylene
maleic anhydride copolymers or linear low, very low and ultra low
density polyethylene copolymers, olefinic unsaturated carboxylic
acids or carboxylic acid derivatives, or polyolefins modified with
anhydride, polyethyl oxazolines or stearyl stearamide, such as
described, for example, in EP-A-406 568 or EP-A-188 123, grafted
polyolefins containing styrene and ethylene butylene blocks, for
example Kraton .RTM. of the Shell company, polyolefins produced
using a metallocene catalyst, random heterophase copolymers, highly
amorphous polypropylenes or mixtures of two or more of the
aforementioned polymers or polymer systems.
Particularly preferred are sealing layers which comprise random
copolymers of propylene with ethylene, butene, hexene and/or octene
as comonomer and/or comprise random heterophase copolymers of
propylene with ethylene, butene, hexene and/or octene as
comonomer.
A different, additionally preferred type is present in terpolymers
consisting of propylene, ethylene and an additional .alpha.-olefin,
in particular butene, nexene and octene.
Particularly preferred are polyolefins grafted with maleic
anhydride as well as copolymers containing styrene and ethylene
butylene blocks and preferably grafted with maleic anhydride, for
example the products of the Mitsui Petrochemicals company marketed
under the brand name Admer.RTM..
At the same time, the aforementioned propylene random copolymers,
the random heterophase copolymers and terpolymers which are
produced using a metallocene catalyst are particularly
preferred.
The sealing layer is preferably coextruded with the lower part
and/or the push-through layer. In this respect, additional
production steps are omitted and a good adhesion of the sealing
layer to the lower part or the push-through layer, respectively, is
ensured.
At the same time, the sealing layer can also be applied to the
push-through layer and/or the lower part as a lacquer coating.
PVC, polystyrene, styrene copolymers, polyester or, in particular,
polyolefins have proven to be suitable plastic materials for the
push-through layer as predominant component.
Particularly preferred materials for the push-through layer are
present in the polypropylenes, above all high crystalline
polypropylenes (HCPP) and, in particular, in the PPs or HCPPs
produced using a metallocene catalyst. These materials are
particularly suitable for forming the main component of the
push-through layer. Suitable, high crystalline polypropylenes are
known, for example, from EP 0255 693 B1 and have a high, isotactic
proportion of pentadene (recommended is the range of 0.955 to 1.0)
(cf. EP 0255 693 B1 for the method of measurement for this).
Preferred polyolefins are to be seen in polypropylenes, and their
particularly good physical properties, such as, for example,
blocking efficiency for steam, transparency, chemical stability
etc.
The average molecular weight of the polymers in the push-through
layer is preferably selected in the range of approximately 10,000
to approximately 600,000.
The module of elasticity (measured in accordance with DIN 53457 on
films 50 .mu.m thick) is preferably 1200-1800 N/mm.sup.2 for the
pure, high crystalline polypropylene to be used in the push-through
layer. In the case of the filled polypropylene matrix the module of
elasticity may increase, for example, to values (in N/mm.sup.2) of
1800 to 2000 with a 5% by weight filling of talc, 2200 to 2400 with
a 10% by weight filling of talc or 3000 to 3400 with a 20% by
weight filling of talc.
The push-through layer advantageously comprises a polymer matrix
with a particulate filler which is selected and contained in such a
proportion in the matrix that the puncture resistance of the
push-through layer is reduced to below a limit of 450 N/mm (method
of measurement according to DIN 53373).
This limit applies for films approximately 150 .mu.m in thickness.
For much thinner or thicker films or push-through layers the
corresponding limits can be derived from these values. In the case
of the specified limit, it is possible to press goods not sensitive
to pressure through the cover film of the goods carrier, even
though with some use of force. In the case of more sensitive
products, a lower limit will preferably be selected for the
puncture resistance, and this value is then preferably at
approximately 50 to approximately 200 N/mm. Lower puncture
resistances may be recommendable in individual cases where goods
very sensitive to pressure are to be packaged. However, it should
be noted in this respect that with the reduction in the puncture
resistance the protective effect of the packaging against damage to
the goods themselves is, of course, decreased and so an optimum for
the majority of the pharmaceuticals to be packaged is to be seen in
the range up to approximately 100 N/mm. The reduction in the
puncture resistance to lower values is, however, a more minor
problem with the present invention since the push-through layer is
still protected by the pull-off layer and is not exposed until the
moment the packaging is opened due to the removal of the pull-off
layer.
For the handling of the packaging by the consumer, i.e. in
particular when opening the packaging and, therefore, the goods, a
further property of the push-through layer comes into play
secondarily, namely the so-called resistance to further tearing
which determines the force requirements necessary to allow a
push-through layer which has been penetrated once to be torn
further open and thus completely release the packaged product. This
property can also by influenced by the selection of the filler as
well as its proportion in the polymer matrix, a resistance to
further tearing of less than 30 N (method of measurement according
to DIN 53363) being preferably aimed at in this case. This
numerical value applies, in particular, for films of approximately
150 .mu.m in thickness but can also be used essentially for
considerably thinner or thicker layers or films. An acceptable
value of the resistance to further tearing for the handling, in
particular, of goods sensitive to pressure as well is between
approximately 2 and 12 N, whereby it should again be noted that, of
course, considerably lower values are possible but any reduction is
subject to limits in view of the protection of the goods by the
push-through layer. A preferred range for the resistance to further
tearing is in the range of 3 to 4 N. Low values for the resistance
to further tearing are, however, again to be seen in conjunction
with the protective effect of the pull-off layer.
The inventive push-through layer contains the filler as a
homogeneous addition to a plastic material which is already
completely polymerized. The filler is not therefore--as known in
conjunction with filler-reinforced plastics--dispersed in the
polymerization reaction mixture consisting of monomer and/or
prepolymer and incorporated into the polymer matrix during
hardening of the reaction mixture. However, it is, of course,
conceivable to use such reinforced plastic material as polymer
matrix in specific applications, also in conjunction with the
present invention.
A broad range of fillers is available for the fillers of the
push-through layer. These can be selected not only from inorganic
but also from organic substances.
Preferred examples for the organic substances are, e.g.,
halogenated hydrocarbon polymers, in particular PTFE, polyether
sulfones, which have, like the PTFE, a melting point of
>300.degree. C., as well as duroplastic materials. In the case
of the organic substances which are intended to serve as fillers,
it is important that these do not liquefy during the processing of
the polymer matrix material, during which temperatures of
220.degree. C. and more can occur, and then form a homogeneous
solution with the polymer matrix material but that these remain
essentially in particle form in the polymer matrix during
processing and thus serve to weaken the continuous polymer matrix
layer and, therefore, to reduce the puncture resistance and, where
applicable, the resistance to further tearing accordingly. On the
other hand, polymers with a lower melting point can also be used as
fillers, where necessary mixed with additional fillers of a
different type, when it must only be ensured that in the case where
not only the matrix polymer but also the filler polymer are
simultaneously present during the processing in a molten state two
separate phases also remain in the melt, similar to the
distribution of an oil-in-water emulsion.
For the inorganic component of the filler, the substance can be
selected from the family of silicon dioxides, in particular in the
form of glass or quartz, silicates, in particular in the form of
talc, titanates, TiO.sub.2, aluminum oxide, kaolin, calcium
carbonates, in particular in the form of chalk, magnesites, MgO,
iron oxides, silicon carbides, silicon nitrides, barium sulfate or
the like.
When selecting the inorganic or organic substances as components of
the filler, the goods to be packaged will always have to be taken
into consideration as well and their sensitivity with respect to
one or other of the additional substances in the polymer
matrix.
The form of the filler particles will most often be granular or
flake-like but fibrous or rod-shaped filler particles are also
possible not only as an essentially unitary form but also in a
mixture with other forms as filler particles.
The particle size of the filler (measured over the greatest
extension of the particle) is preferably, on average, approximately
5 to approximately 100 .mu.m. The selection of the particle size
is, of course, also determined to a not inconsiderable extent by
the thickness of the layer to be produced. Care will thus need to
be taken that the average extension of the particles keeps a clear
distance in relation to the thickness of the layer to be produced.
Average particle sizes of between 20 .mu.m and 60 .mu.m, in
particular with layer thicknesses of 80 .mu.m to 100 .mu.m, are
preferred.
In order to ensure that the filler does not lead to a reinforcement
of the polymer matrix, care should be taken that the filler
particles adhere as little as possible to the polymer matrix.
However, the adhesion forces between the particles and the filler
matrix should at least be clearly less than the tensile strength of
the matrix itself. Care will therefore have to be taken, in
particular, in the case of the inorganic filler particles that
these are essentially free from so-called adhesive agents. Such
adhesive agents are customarily used for the production of filled
plastics, with which the focus is, however, on the particular
strength of the material.
On the other hand, the aim is, of course, for the filler particles
to be distributed in the polymer matrix as evenly as possible and
for this distribution to also be maintained during the production
process and so supplementary agents which improve the
dispersibility of the filler particles in the matrix are preferably
added.
Particularly suitable as dispersing agents are organic substances
which have a low melting point and a large wetting capability for
the filler. Concrete examples are low-molecular polyolefin waxes.
The dispersing agents are preferably applied to the filler
particles before these are mixed, in particular, kneaded with the
granulate of the matrix polymer.
The thickness of the push-through layer is preferably selected to
be from 20 .mu.m to approximately 600 .mu.m which, on the one hand,
ensures an adequate stability of the push-through layer for
protecting the packaged goods and, on the other hand, keeps the
forces necessary for opening the packaging within the prescribed
limit, within which at least goods insensitive to pressure can
still be removed from the packaging by the average buyer without
any problem by pushing them through the push-through layer.
The push-through layers on a polymer basis described thus far
achieve the push-through property in that fillers were embedded in
the matrix which were selected with a view to their composition and
their proportion such that a weakening of the polymer matrix
surrounding them occurred, whereby the puncture resistance of the
film was reduced to such an extent that the packaged goods may be
pressed through the film due to this tearing or breaking open. This
generally required, in addition, an optimization of the fillers and
their proportion with respect to the resistance to further tearing
of the film. Inorganic and organic fillers were suggested as
fillers, whereby for organic materials it was recommended that an
organic second phase be used which, if present in a liquid form, is
maintained during melt extrusion as a second phase within the first
phase in the case of the extruded film.
Due to the requirement that the push-through property of the
push-through layer should be ensured by the selection of the
fillers and, in particular, their proportions in the polymer matrix
as well, push-through layers resulted which are always opaque. The
light impermeability of the layers is based essentially on the fact
that within the layer material a large number of boundary surfaces,
i.e. the boundary surfaces between the polymer matrix and the
inserted phase/filler, at which reflections, dispersion etc. occur,
prevent any passage of light and, therefore, any transparency of
the material even with slight layer thicknesses.
In addition, the selection of the fillers or rather the second
phase in the matrix was always limited by the fact that the
corresponding push-through properties of the push-through layers,
such as, for example, the reduction in the puncture resistance to
specific values or also the reduction in the resistance to further
tearing, had to be ensured by way of the selection of the
filler/the organic material which was intended to form the second
phase.
In many cases, it is, however, desirable, in order to achieve
specific qualities of a film, to have a free hand when selecting
fillers and their proportions which are to be added, or, however,
it may be desirable to produce transparent push-through films which
would make a new type of push-through packaging possible.
Push-through layers, which fulfill such a requirement, imply that
the polymer phase (preferably polyolefin) contains a hydrocarbon
resin component in a dissolved form, wherein the hydrocarbon resin
component is different to the polymer of the polymer phase,
comprises cyclic side groups on the polymer chain and is contained
in the push-through layer with a proportion of at least
approximately 3% by weight of the total mass and wherein the
average molecular weight of the hydrocarbon resin component (B)
.ltoreq.10,000.
This push-through layer therefore represents, in contrast to what
has been described thus far, a single-phase material and no longer
attains the push-through capability in an interruption of the
continuous polymer phase by a plurality of filler particles but by
the embrittlement due to the increase in the glass transition
temperature by way of dissolution of a selected hydrocarbon resin
component in the polymer phase.
This means that the possibility is created for the first time of
producing transparent push-through layers or of filling the
push-through layers with fillers, the selection of which can be
made completely independently of the desired push-through
properties of the layer.
In this respect, the polyolefin of the polymer phase or rather the
polyolefin phase acts as the solvent phase while the hydrocarbon
resin is present in this phase dissolved in the end product. It has
been shown that, in order to obtain adequate push-through
properties, at least approximately 3% by weight of the hydrocarbon
resin component must be added to the solvent phase, i.e. the
polyolefin.
The polyolefin of the polyolefin phase preferably comprises
polyethylene, polypropylene, including high crystalline PP as well
as nucleated PP, copolymers and terpolymers of ethylene, propylene
and/or higher .alpha.-olefins.
Approximately 3% by weight of the hydrocarbon resin component (B)
are already completely sufficient, for example, in those cases, in
which nucleated PP is used as polyolefin (A).
Examples of suitable nucleation agents are talc, sodium benzoate,
sorbite derivatives, organic phosphates, such as, for example,
sodium 2,2'-methylene-bis-4,6-di-tert-butyl phenyl phosphate,
benzoic acid derivatives, cross-linked polypropylene as well as
mixtures of the aforementioned nucleation agents.
During the production of this type of push-through layer, a
so-called .alpha.-nucleation agent is preferably added during
compounding, i.e. during the adding of the resin and, where
applicable, the fillers. Alternatively, a polyolefin (A) which is
already nucleated can be used as initial material. The proportion
of the nucleation agent is normally in the range of approximately
50 ppm to 1% by weight in relation to the total weight of the film
and is preferably in the range of 0.05 to 0.5% by weight. The
effect of the .alpha.-nucleation agents is in increasing the
crystallization speed of the polyolefin component (A) which results
in a higher rigidity of the material and a lower puncture
resistance.
The low value for the molecular weight of the hydrocarbon resin
component (B) is at approximately 500 while a preferred upper limit
is at approximately 5,000. If hydrocarbon resin components with a
molecular weight of lower than 500 are selected, a certain
stickiness results not only of this component but also of the
resulting film product.
The total content of the hydrocarbon resin component (B) in the
finished film is at the most approximately 25-30% by weight.
Proportions higher than this are possible in principle but make the
production more expensive and so the profitability of the film is
then questionable.
The push-through layers described first of all, in particular those
filled with inorganic fillers, occasionally cause problems during
production when the filler content is high since this can lead to
deposits of the solid fillers in the extruder nozzle. This applies
in part during the use of filler contents of >45% by weight.
Such deposits do not occur during the production of single-phase
push-through layers.
Advantages of the single-phase push-through layer are to be seen in
their improved processability which is attributable, in particular,
to the possible low contents of fillers. In conjunction therewith,
the single-phase push-through layer can be produced in thinner
layers, for example layers 30 .mu.m thick can be produced without
problem and even layers 15 .mu.m thick and thinner layers can be
produced without more special measures. In this respect, there are
clear limitations in the case of the push-through layers filled
with inorganic fillers since, in this case, the grain diameter of
the fillers must be taken into consideration. In addition, not only
are undrawn layers, such as those known from the state of the art,
suitable as a push-through layer but also drawn layers. Drawn
push-through layers have, in particular, the advantage that the
rigidity, the optical appearance (luster), the transparency,
barrier properties against steam and the resistance to low
temperatures are improved.
One example for the independent selection of the fillers for
achieving special effects in the case of the inventive push-through
layers is that very fine fillers may be selected (also in the case
of very thin layers) which, in the state of the art, have sometimes
increased the viscosity of the layer and, therefore, have increased
the puncture resistance instead of reducing it. Very fine fillers
ensure a smooth surface of the layer.
The cyclic side groups on the polymer chain of the hydrocarbon
resin component (B) discussed in the above and also these polymers
themselves can be present partially or completely hydrogenated. For
example, these hydrocarbon resins can be amorphous, low-molecular
polymers consisting of, for example, petrochemical raw materials.
They may be formed from aliphatic and/or aromatic monomers, such
as, e.g., styrene, vinyltoluene or alphamethylstyrene as well as
additional aromatic hydrocarbons with substituted vinyl groups.
These polymers can be homopolymers, copolymers as well as polymers
with an optional number of monomers and have a broad spectrum of
molecular weights.
The basis for the hydrocarbon resin component can, however, also be
formed by natural products, such as, for example, colophony resins.
Such products are, for example, offered by the Herkules company
under the brand names "Regalrez" or "Regalite".
A preferred weight proportion of the hydrocarbon resin component
(B) in the film is at 5 to 10% by weight. The hydrocarbon resin
component is preferably an amorphous material.
Preferred, transparent push-through layers consist essentially of
the polyolefin phase (A) and the hydrocarbon resin (B). Such
push-through layers have an excellent transparency, very good
printing properties and still have a puncture resistance which
recommends their use even for sensitive pharmaceuticals in tablet
form.
The possible filler content of the single-phase push-through layer
already discussed in the above can be varied in the range of 0 to
35% by weight, the upper limit preferably being drawn at
.ltoreq.30% by weight, even better at 25% by weight. Particles with
an average particle size in the range of 1 .mu.m to 60 .mu.m are
used as fillers, this value being dependent, on the one hand, on
the selected filler and, on the other hand, on the desired layer
thickness. Preferred materials for fillers are, from the inorganic
range, chalk and talc.
The molecular weight of the polymer which forms the solvent phase,
i.e. the solvent polyolefin, is preferably .gtoreq.10,000. An upper
limit for this is to be set at approximately 1.2 million,
preferably at 600,000.
No details have so far been given concerning the concrete design of
the peelable connection of pull-off layer and push-through layer.
Several alternatives can be considered in this respect.
On the one hand, the peelable connection can be designed as a
separate layer as a seal/peel layer. On the other hand, it is
likewise possible to obtain the peelable connection by coextruding
pull-off layer and push-through layer with a corresponding
formulation of the two layers.
If the seal/peel layer is chosen as the peelable connection of
pull-off layer and push-through layer, this can then be coextruded
together with the pull-off layer and/or the push-through layer or
applied to the pull-off layer or the push-through layer as a
separate layer, for example as a type of adhesive layer or also as
a lacquer coating.
Preferred seal/peel layers comprise a mixture consisting of two
incompatible polymer components I and II, wherein the component I
is a propylene homopolymer or a copolymer of ethylene and propylene
or ethylene and butylene or propylene and butylene or ethylene and
a different .alpha.-olefin with 5 to 10 carbon atoms or propylene
and a different .alpha.-olefin with 5 to 10 carbon atoms or a
terpolymer of ethylene and propylene and butylene or ethylene and
propylene and a different .alpha.-olefin with 5 to 10 carbon atoms
or a mixture of two or more of the specified homopolymers,
copolymers and terpolymers or a blend of two or more of the
specified homopolymers, copolymers and terpolymers, where
applicable mixed with one or more of the specified homopolymers,
copolymers and terpolymers and wherein the component II is
preferably a high density polyethylene, medium density
polyethylene, low density polyethylene, linear low density
polyethylene, very low density polyethylene or ultra low density
polyethylene which are produced, in particular, using a metallocene
catalyst.
The component I of the peelable mixture or the blend is
essentially
a propylene homopolymer or
a copolymer of
ethylene and propylene or
ethylene and butylene or
propylene and butylene or
ethylene and a different .alpha.-olefin with 5 to 10 carbon atoms
or
propylene and a different .alpha.-olefin with 5 to 10 carbon atoms
or
a terpolymer of
ethylene and propylene and butylene or
ethylene and propylene and a different .alpha.-olefin with 5 to 10
carbon atoms or
a mixture of two or more of the specified homopolymers, copolymers
and terpolymers or
a blend of two or more of the specified homopolymers, copolymers
and terpolymers, where applicable mixed
with one or more of the specified homopolymers, copolymers and
terpolymers.
As particularly preferred, the component I consists essentially
of
a copolymer of
ethylene and propylene or
ethylene and butylene-1 or
propylene and butylene-1 or of
a terpolymer of
ethylene and propylene and butylene-1 or of
a mixture of two or more of the specified,
particularly preferred homopolymers, copolymers and terpolymers or
of
a blend of two or more of the specified,
particularly preferred homopolymers, copolymers and terpolymers,
where applicable mixed with
one or more of the specified homopolymers, copolymers and
terpolymers,
wherein, in particular, propylene homopolymer or
random ethylene propylene copolymers with
an ethylene content of 1 to 15% by weight, preferably 5 to 8% by
weight, or
random propylene butylene-1 copolymers with
a butylene content of 4 to 25% by weight, preferably 10 to 20% by
weight,
each related to the total weight of the copolymer, or
random ethylene propylene butylene-1 terpolymers with
an ethylene content of 1 to 10% by weight, preferably 2 to 6% by
weight, and
a butylene-1 content of 3 to 20% by weight, preferably 8 to 10% by
weight,
each related to the total weight of the terpolymer, or a blend of
an ethylene propylene butylene-1 terpolymer and
a propylene butylene-1 copolymer
with an ethylene content of 0.1 to 7% by weight
and a propylene content of 50 to 90% by weight
and a butylene-1 content of 10 to 40% by weight,
each related to the total weight of the polymer blend, are
preferred.
The propylene homopolymer used as or in the component I
predominantly contains propylene (at least 90% by weight) and has a
melting point of 140.degree. C. or higher, preferably 150 to
170.degree. C., wherein isotactic homopolypropylene with a content
soluble in n-heptane of 6% by weight and less, related to the
isotactic homopolypropylene, is preferred. The homopolymer of the
component I or the homopolymer contained therein generally has a
melt-flow index of 1 g/10 min to 30 g/10 min, preferably 1.5 g/10
min to 6 g/10 min, measured at 230.degree. C. and a force of 2.16
kg (DIN 53 735).
The copolymers described in the above generally have a melt-flow
index of 1.0 to 30 g/10 min, preferably from 3 to 15 g/10 min. The
melting point is in the range of 120 to 155.degree. C. The
terpolymers used in the layer/layers have a melt-flow index in the
range of 1.5 to 30 g/10 min, preferably from 3 to 15 g/10 min, and
a melting point in the range of 120 to 140.degree. C. The blend
described above and consisting of copolymers and terpolymers has a
melt-flow index of 5 to 9 g/10 min and a melting point of 120 to
150.degree. C. All the melt-flow indices specified above are
measured at 230.degree. C. and a force of 2.16 kg (DIN 53 735).
Other layers consisting of copolymers and/or terpolymers preferably
form the cover layers of sealable embodiments of the film.
The component II of the peelable mixture is a polymer which is
incompatible with the olefin polymers described in the above and is
essentially built up from ethylene sequences. "Incompatible
polymer" means in the sense of the present invention that the
incompatible polymer is present as a separate phase besides the
olefin polymer. Preferred are high density polyethylene, medium
density polyethylene, low density polyethylene, linear low density
polyethylene, very low density polyethylene and ultra low density
polyethylene. These ethylene polymers generally contain a small
proportion of <25% by weight, preferably 1 to 15% by weight, of
comonomer. Olefins with 3 to 10 C-atoms are suitable as comonomers,
wherein The incompatible polymer is likewise preferably a
polyolefin, for example built up on the basis of ethylene, wherein
the component I or the basic matrix is based on propylene.
The blend displays two or more separate melting peaks in a melting
diagram recorded by means of differential scanning calorimetry. The
first melting peak is in the range of 105 to 135.degree. C., the
second and possibly third melting peaks in the range of 120 to
170.degree. C.
The ratio (weight ratio) of the two incompatible polymer components
I and II of the mixture or the blend can be varied within broad
limits depending on the desired peeling force. The ratio of the
components I and II is preferably in a range of I:II=5:95 to
I:II=95:5, preferably between I:II=30:70 to I:II=70:30, in
particular at I:II=50:50.
The seal/peel layer can alternatively consist of a mixture which
comprises:
a1) 30 to 80% by weight of a polymer mixture, consisting of
a1.1) 60 to 98% by weight of a crystalline copolymer consisting of
propylene with ethylene and/or an .alpha.-olefin of the general
formula CH.sub.2 --CHR, wherein R is a linear or branched alkyl
radical with 2 to 8 carbon atoms, containing 85 to 99.5% by weight
of propylene and
a1.2) 2 to 40% by weight of an elastic copolymer consisting of
ethylene and propylene and/or an .alpha.-olefin of the general
formula CH.sub.2 --CHR, containing 20 to 70% by weight of ethylene
or
a2) 30 to 80% by weight of a highly amorphous polypropylene with a
crystalline polypropylene proportion of up to 10% by weight with a
melting enthalpy of at the most 40 J/g and a melt-flow index of
between 0.1 and 100 g/10 min, wherein the polypropylene can be a
homopolymer of the propylene or a copolymer of the propylene with
one or more .alpha.-olefins and a propylene proportion of at least
80 mol %, and
a3) 70 to 20% by weight of an incompatible ethylene
polymerisate.
The peelability is preferably given at a force initiation of less
than 30 N/15 mm.
The peeling force for removing the pull-off layer from the closed
pharmaceutical packaging should not, as far as possible, exceed 5
N, preferably 3 N and even more preferred 2 N at a peeling front 22
mm in width in order to make the opening of the packaging easy even
for patients handicapped by illness.
In addition, the seal/peel layer should withstand sealing
temperatures of up to 180.degree. C. without the peeling properties
altering noticeably.
A broad range of materials is suitable for the pull-off layer which
has not so far been discussed in detail. In this respect, however,
pull-off layers are particularly preferred which are produced from
a thermally stable material, in particular unfilled and filled
polypropylene homopolymer, high crystalline polypropylene, paper,
or preferably oriented filled or unfilled polyamide, polyester, or
polypropylene.
The cover film can have, apart from the pull-off layer and the
push-through layer, a heat-resistant protective layer (such as, for
example, a protective lacquer) for protecting printings on the
cover film or for avoiding adhesion to sealing tools.
For a great number of applications, in particular for the packaging
of pharmaceuticals, the lower part of the packaging should be
sealed to the cover film along sealing seams around the individual
goods so as to be essentially moistureproof and, where necessary,
essentially oxygen-tight.
For the purpose of facilitating the opening of the packaging, the
cover film should have a tear-initiation area which is designed,
for example, such that the cover film can first of all be grasped
as a whole but during removal of the cover film the pull-off layer
of the cover film is separated from the push-through layer along
predetermined contours and the pull-off layer can be detached
further on its own. This has the special advantage that the
tear-initiation area contains not only the pull-off layer but also
the push-through layer, whereby a thicker layer which can be
gripped more easily is available in the tear-initiation area.
The contours of the tear-initiation area are preferably designed as
an interrupted line, a saw tooth or wavy shape or an angular shape
directed contrary to the pull-off direction. This means that at the
beginning of the separation of pull-off layer and push-through
layer less force is necessary since, first of all, the separation
only takes place essentially punctually or in the region of a
narrow peeling front and the complete separation of the entire
peeling front occurs only during the course of further tearing.
In order to facilitate the gripping of the tear-initiation area, it
is preferably provided for an easily grippable section or surface
area of the cover film to be designed as a grip tab and not to be
sealed to the packaging lower part. In order, however, to avoid any
unintentional initial tearing in such an embodiment, it is
suggested that the grip tab be connected, where necessary, with the
packaging lower part via one or several sealing points having a
small area to ensure the plane state.
In the case of the cover film, the pull-off layer is advantageously
connected in an areal or stippled manner to the seal/peel layer and
the push-through layer by means of a thermolaminating process.
For packaging products sensitive to oxygen, an oxygen barrier layer
can be incorporated not only in the packaging lower part but also
in the cover film.
This can consist, for example, of polyamide, polyethylene
terephthalate, ethyl vinyl alcohol, PVDC, PVDF. It is also possible
to metallize the cover film as well as apply metal oxide layers
consisting of SiO.sub.x, MgO.sub.x, or Al.sub.z O.sub.x which can,
where necessary, also be lacquered.
FIG. 1 shows an inventive packaging which is provided as a whole
with the reference numeral 10 and comprises a packaging lower part
12 with recesses or small pockets 14 which are formed in a
deep-drawing process for accommodating individual goods and a cover
film which is designated as a whole with the reference numeral 16
and is sealed onto the lower part 12 once the goods, for example
tablets or capsules, have been arranged in the small pockets
14.
The cover film in this example is made up of a push-through layer
18, a pull-off layer 20, a seal/peel layer 24 arranged between the
push-through layer 18 and the pull-off layer 20 and a sealing layer
22 arranged on the underside of the push-through layer.
In this respect, the push-through layer 18 is preferably coextruded
together with the sealing layer 22 and the seal/peel layer 24.
Subsequently, the pull-off layer which is produced separately is
applied to the push-through layer coextrudate in a separate
laminating step. In this case, a connection over the entire surface
can be achieved or, if desired, a stippled or rather punctual
connection can be produced between the push-through layer
coextrudate and the pull-off layer.
The cover film 16 produced in this manner is then sealed onto the
packaging lower part 12 as described above.
In the cover film 16, the seal/peel layer undertakes a dual
function in that it, on the one hand, provides for the cohesion of
the cover film layers and, on the other hand, produces a peelable
connection between the push-through layer 18 and the pull-off layer
20.
FIG. 2 shows an illustration of an inventive tablet blister pack 30
which follows, in principle, the construction described in
conjunction with FIG. 1. The blister pack has a cover film 34
sealed to a packaging lower part 32. The sealing is thereby carried
out such that a sealing surface results around the small pockets 36
integrally formed in the packaging lower part 32 which is
essentially moistureproof and, preferably, also oxygen-tight. In
the sealing tool, the cover film supported on the deep-drawn film
of the packaging lower part surrounding the small pockets is
pressed such that its originally honeycomb-like pattern, which
originates from a stippled sealing of push-through layer and
pull-off layer, is essentially flattened.
The tablet blister 30 is designed to be dividable via perforation
lines 40, 40a so that each individual tablet can be separated from
the overall packaging together with the packaging part surrounding
it.
On both sides of the perforation line 40a forming the packaging
longitudinal axis, care is taken by way of a corresponding
contouring of the sealing tool or the sealing receiving means that
no or only a slight sealing results between the cover film 34 and
the packaging lower part 32. These regions 42 of the cover film
which are not or only slightly sealed form grip tabs which are
accessible once a packaging portion has been separated from the
overall blister pack.
The boundary line 44 between the grip tab 42 and the rigidly sealed
regions of the cover film 34 around the small pockets 36
accommodating the tablets 38 preferably deviates from the form of a
straight line so that when the cover film is removed from the
packaging only a relatively narrow peeling front results first of
all, at which the separation of pull-off layer and push-through
layer must take place. In this way, the peak forces occurring
during the removal and separation of these layers may be reduced
without problem to a value below 10 N. This means that not only is
a simple peelability realized but, in particular, an essential
precondition created so that during the separation of these layers
the push-through layer remains reliably sealed to the blister lower
part.
The boundary lines 44 can have the slightly curved shape shown in
FIG. 2 but they can also extend at an angle pointing towards the
perforation line 40a or be designed in the shape of a wavy line
with a relatively small wave length or any other suitable line
shape which achieves the purpose defined above of a relatively
narrow peeling front at the beginning of the separation
procedure.
Finally, FIG. 3 shows a capsule blister 50 with a completely
transparent blister lower part 52 and a likewise completely
transparent cover film 54. The capsules are accommodated in small
pockets 56 which have been formed in the blister lower part by way
of thermoforming. Around the small pockets 56 the cover film 54 is
again sealed over the entire surface with the blister lower part,
although along the central axis of the blister 50 regions 58 of the
cover film 54 remain unsealed in order to form grip tabs. The
blister pack can again, as already described for the blister shown
in FIG. 2, be separated along perforation lines 60, 60a and the
capsules may be removed analogously to the tablets of the blister
of FIG. 2, for which reason reference is made to the above
description with respect to details. The separation of the cover
film 54 into pull-off layer and push-through layer results during
opening of the individual blister section along the line 62 which
forms at the same time the boundary line for the grip tabs.
EXAMPLES
The inventive packaging will be explained in greater detail in the
following on the basis of examples:
Production of the Push-Through Layer
In a first step, a polymer granulate is mixed with the filler
amounts and subsequently extruded or calendered. The mixing, in
particular the homogenization, can take place by means of kneading
in accordance with known processes, in particular twin-screw
compounding. The individual components can, however, also be mixed
with one another in a dry mixing process. A better homogeneity,
i.e. a more even distribution of the fillers in the polymer matrix,
is achieved by means of the preceding production of a so-called
compound.
Treatment of the filler particles with dispersing agents should
take place, in any case, prior to the blending with the matrix
polymer.
The compound is melted in the extruder, namely at melt temperatures
of approximately 220.degree. C. and more as well as at a melt
pressure of up to 250 bar. The melt is preferably cooled over a
chill roll at 20.degree. C. to approximately 80.degree. C. but
other cooling processes, where necessary with a surface treatment
combined with a corona pretreatment, are also possible.
The push-through layer is then cut and wound.
When polypropylene is used as polymer, a homopolymer polypropylene
having a melt-flow index of 2 to 10 g/10 min in accordance with DIN
53735 (230.degree. C./2.16 kg) and a density (23.degree. C.) in
accordance with DIN 53479 of 0.900 to 0.910 g/cm.sup.3 may be
mentioned as an example. Types of polypropylene differing from
this, such as, for example, block copolymers or random copolymers,
can, of course, be used.
Chalk or talc is suggested as filler for this example with an
average particle size or 5 to 60 .mu.m, better still with an
average particle size of 20 to 30 .mu.m. The proportion of fillers
in the overall layer weight is preferably from 25 to 55% by weight.
Below a filler proportion of 20% by weight, an adequate
embrittlement of the polymer with the reduction in the puncture
resistance and the resistance to further tearing connected thereto
is normally no longer attained. With proportions clearly above 60%
by weight, the production of the film becomes difficult and the
physical resistance values are often no longer adequate for the
typical uses.
As is customary in the production of polypropylene films, a
rewinding is also carried out with the inventive push-through layer
on a polypropylene basis for reasons of postcrystallization.
With a mixture of
50% by weight of polypropylene, homopolymer and
50% by weight of talc as filler, average particle size
20 .mu.m, a film 150 .mu.m thick was produced.
A puncture resistance of 162 N/mm and a resistance to further
tearing of 3.2 N could be measured on this film.
From a mixture of
75% by weight of polypropylene, homopolymer and
25% by weight of talc as filler, average particle size
20 .mu.m, a film 150 .mu.m thick was produced.
A puncture resistance of 405 N/mm and a resistance to further
tearing of 12 N could be measured on this film.
A different type of push-through layer can be obtained as
follows:
As an alternative example for the polymer of the polymer matrix, a
high crystalline polypropylene with a melt-flow index of
approximately 8 g/10 min in accordance with DIN 53735 (230.degree.
C./2.16 kg) and a density (23.degree. C.) in accordance with DIN
53479 of 0.902 g/cm.sup.3 may be mentioned. Types of polypropylene
differing from this can, of course, be used.
Chalk or talc is suggested as filler for this example with an
average particle size of 5 to 60 .mu.m, better still with an
average particle size of 20 to 30 .mu.m. The proportion of fillers
in the total film weight is preferably from 10 to 55% by weight.
Below a filler proportion of 5% by weight, an adequate
embrittlement of the polymer with the reduction in the puncture
resistance and the resistance to further tearing connected thereto
is normally no longer attained. With proportions clearly above 60%
by weight, the production of the film becomes difficult and the
physical resistance values are often no longer adequate for the
typical uses.
The processing can also take place with these materials as
described above.
As is customary in the production of polypropylene films, a
rewinding is also carried out in this case with the push-through
layer on a polypropylene basis for reasons of
postcrystallization.
With a mixture of
95% by weight of polypropylene, highly crystalline, of the Mitsui
company with the product brand name CJ700, and
5% by weight of talc as filler, average particle size
20 .mu.m, a film 150 .mu.m thick was produced (density 0.93
g/cm.sup.3)
A puncture resistance of 360 N/mm and a damage energy in accordance
with DIN 53373 of 0.5 J/mm could be measured on this film.
From a mixture of
90% by weight of polypropylene, highly crystalline, of the Mitsui
company with the product brand name CJ700, and
10% by weight of talc as filler, average particle size
20 .mu.m, a film 150 .mu.m thick was produced (density 0.965
g/cm.sup.3).
A puncture resistance of 220 N/mm and a damage energy of 0.2 J/mm
could be measured on this film.
If the mixture is adjusted to 80% by weight of polypropylene
(specification see above) and 20% by weight of talc (specification
see above), a puncture resistance of approximately 100 N/mm as well
as a damage energy of 0.05 J/mm are obtained. The density of the
material was determined at 1.04 g/cm.sup.3.
A further alternative for the production of the push-through layer
is described in the following, the push-through property being
achieved with a single-phase polymer system and fillers serving
only to optimize additional properties.
Production of the compound
The propylene polymers used in Examples 1 to 19 were mixed in
powder form in an intensive mixer with 0.05% by weight of
tris-(2,4-di-tert-butyl phenyl)-phosphite as processing stabilizer,
0.05% by weight of
pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)
-propionate] as long-term stabilizer and 0.1% by weight of calcium
stearate as well as with the respective resins and/or fillers as
well as, where applicable, the nucleation agent and kneaded on a
twin-screw extruder with a screw diameter of 50 mm and a l/D ratio
of 15 D (type Collin ZK 50) at a melt temperature of 230.degree. C.
and subsequently granulated.
Production of the push-through film
The principle underlying the chill roll process is that a melt
plasticated and homogenized in the extruder is continuously
extruded under pressure from a slot die, the melt being brought
into the rigid state on a cooling roll and the flat film being
wound in the winding unit to form a roll.
The plastication of the granulate takes place in that a screw
continuously conveys the plastic material through the heated
cylinder zones, and the plastic material is thereby transformed
into the state of a homogeneous compressed melt. A subsequent
filter unit ensures the required build up of pressure in the
cylinder and filters any impurities out of the melt.
The homogenized melt is conveyed further into a slot die where it
is distributed such that it exits uniformly from the die slot.
The shaping of the flat film takes place by drawing the melt out of
the slot die by means of a rotating chill roll (cooling roll 1)
which is cooled evenly over its width, the melt being cooled upon
contact with the roller and brought into the rigid state. The flow
of air exiting out of the air blade, where necessary assisted by a
suction blade, fixes the melt along a surface line on the cooling
roll 1, thereby ensures good contact with the roll and thus
initiates a uniform cooling of the melt.
A cooling roll with a larger film angle of wrap (cooling roll 1),
combined with one or two subsequent cooling or attemperating rolls,
is mainly used.
The mechanical and optical film properties are determined according
to the cooling conditions of the film, the cooling roll 1 thereby
having the greatest influence on the film properties.
Depending on the nature of the plant, the film is guided at a
regulatable film tension over a thickness measuring device, an
annealing station, film laying unit, cutting station, surface
pretreatment station into the winding station where the film is
then wound to form a film roll.
During this examination, the brittle character of the resinous
mixtures likewise becomes visible. With an increasing amount of
resin, considerably less force is necessary to penetrate the
films--in addition, the distance until rupture of the film is
considerably shorter than with the non-modified mixture.
In the following Table 1, the results are summarized which were
determined on the films 30 .mu. and 50 .mu. thick at a chill roll
temperature of 15.degree. C. The test results were obtained with
the Dynatest (DIN 53 373).
TABLE 1
__________________________________________________________________________
Film Thickness: 30 .mu. Film Thickness: 50 .mu. Fs Fs/D Wges/D Lges
Fs Fs/D Wges/D Lges Resin (B) N N/mm J/mm mm N N/mm J/mm mm
__________________________________________________________________________
0% 16.8 552 1.2 4.8 49.6 965 9.6 17.1 5% R. 1128 14.1 458 0.8 3.8
34.6 715 2.4 6.8 10% R. 1128 9.1 311 0.4 2.6 19.9 398 0.6 3.6 15%
R. 1128 7.6 257 0.3 2.3 13.2 272 0.3 2.7 20% R. 1128 6.5 215 0.2
2.0 11.3 223 0.2 2.4 25% R. 1128 5.4 185 0.2 1.8 9.1 193 0.2 2.1
10% R 125 9.4 318 0.4 2.7 17.8 357 0.5 3.3 15% R 125 8.2 270 0.3
2.4 13.0 263 0.3 2.6 20% R 125 6.5 217 0.2 2.1 10.8 221 0.2 2.3 10%
R125/nuc 9.2 0.4 2.6 16.7 334 0.4 3.1 0%/(A) nuc. 17.1 576 1.5 5.3
33.0 678 2.7 7.6
__________________________________________________________________________
The type Daplen DM 55, a polypropylene homopolymer with a melt-flow
index (230/2.16) of 2.8 g/10 min, served as reference system and
polymer (A) in the examples of Table 1.
The chill roll temperatures used for the production of the
push-through film are listed in the following Table 2 as well as a
plurality of parameters of the films thereby obtained.
The thickness of the films is 150 .mu.m in Examples 1 to 19 and
Comparative Example VI and 50 .mu.m in Comparative Example V2 as
well as Example 20.
The following have the specified meanings in Tables 1 and 2:
B powder: Propylene homopolymer with a melt-flow index (230/2.16)
of 0.3 g/10 min
D powder: Propylene homopolymer with a melt-flow index (230/2.16)
of 2.5 g/10 min
K powder: Propylene homopolymer with a melt-flow index (230/2.16)
of 8.0 g/10 min
SVA 127: Propylene homopolymer with a melt-flow index (230/2.16) of
35 g/10 min
SVA 198: Propylene homopolymer with a melt-flow index (230/2.16) of
8.0 g/10 min with increased crystallinity
R 1128: hydrous hydrocarbon resin with a molecular weight of 2070
g/mol (weight average)
R 125: hydrous hydrocarbon resin with a molecular weight of 1200
g/mol (weight average)
R 101: hydrous hydrocarbon resin with a molecular weight of 820
g/mol (weight average)
R 1139: hydrous hydrocarbon resin with a molecular weight of 3170
g/mol (weight average)
Piccotac 115: hydrous hydrocarbon resin with a molecular weight of
2500 g/mol (weight average)
These products can be obtained from the Hercules company.
NA 11 UF : Sodium 2,2'-methylene-bis-(4,6-di-tertiary-butyl
phenyl)phosphate (Asahi Denka company/Japan)
Talc A3: Talc with an average particle size of 3 .mu.
Talc A20: Talc with an average particle size of 20 .mu.
Talc A60: Talc with an average particle size of 60 .mu.
The above-mentioned types of talc are products of the Naintsch
company, Austria.
Calcitec M5: Chalk with an average particle size of 5 .mu.
The parameter Wges/D corresponds to the penetration energy.
Alternatively to the fillers specified in Table 2, the following
may be used with push-through force values within the range of the
invention:
inorganic fillers
carbonates (chalk, dolomite)
barium sulfate
talc
mica
kaolin
wollastonite
silicates (glass beads, glass fibers)
organic fillers
synthetic fibers (e.g. polyamide, Kevlar)
natural fibers (e.g. flax or cellulose fibers)
wood flour
The push-through layers described above can, as described first of
all, be coextruded as such or together with a sealing layer and/or
a seal/peel layer.
A pull-off layer, which can, where necessary, bear a seal/peel
layer, is then laminated onto the push-through layer to form a
cover film.
Alternatively, the pull-off layer can also be coextruded together
with the push-through layer and additional function layers to form
a cover film.
The packaging lower part is produced in the conventional manner
from a deep-drawn film and has, where necessary and as described
above, a sealing layer.
Once the recesses accommodating the goods have been filled, the
packaging lower part is sealed to the cover film, the sealing tool
being contoured such that a continuous seal around the individual
recesses in the lower part is achieved but, on the other hand,
surface regions of the cover film remain unsealed or only slightly
or punctually sealed in order to thus form grip tabs.
The contour of the sealing tool also takes into consideration the
fact that peeling fronts which are as narrow as possible are to be
formed at the beginning of the separation of pull-off layer and
push-through layer (cf. description of the drawings).
TABLE 2
__________________________________________________________________________
Chill Roll Temperature; 60.degree. C./150.mu. MFI Elmendorf
Dynatest DIN 53735 ISO 6383/2 DIN 53373 Polymer Nucleation (230/2)
Long. Cross Fs Fs/D Wges/D Lges No. (A) Resin (B) Agent Filler
[g/10'] N/MM N/MM N N/mm J/mm mm
__________________________________________________________________________
1 B powder 25% R 1128 1.4 4.6 5.6 42.0 280.5 0.3 3.0 2 SVA 127 10%
R 1128 50.0 2.9 3.0 43.7 294.3 0.4 3.1 3 SVA 127 25% R 1128 95.0
2.3 2.3 33.2 214.2 0.2 2.6 4 D powder 10% R 125 0.005% NA 11 UF 4.2
3.4 3.6 51.9 343.7 0.4 3.3 5 D powder 10% R 125 0.5% talc A3 4.4
3.2 3.7 44.7 306.7 0.4 3.1 6 K powder 10% R 125 2% talc A20 11.8
2.8 2.8 41.6 277.7 0.3 2.8 7 K powder 10% R 125 25% talc A20 13.0
2.8 2.6 30.6 206.7 0.2 2.4 8 K powder 10% R 125 30% talc A20 12.5
2.1 2.4 30.5 198.7 0.2 2.3 9 K powder 10% R 125 35% talc A20 10.5
2.1 2.3 26.6 175.4 0.2 2.1 10 K powder 10% R 125 35% talc A3 9.5
2.2 2.4 20.7 139.5 0.1 1.8 11 K powder 10% R 125 35% talc A60 13.0
1.9 2.2 14.7 98.6 0.1 1.8 12 K powder 10% R 125 35% Calcitec M5
11.0 2.4 2.7 48.9 348.5 0.7 4.3 13 D powder 25% R 101 7.1 2.8 3.1
41.7 273.1 0.3 2.9 14 D powder 25% R 1139 7.8 2.9 3.2 39.2 263.3
0.3 2.8 15 D powder 25% Piccotac 115 7.1 3.0 3.4 38.2 263.5 0.3 2.9
16 SVA 198 1% R 125 9.0 3.9 4.9 90.9 612.7 1.1 4.7 17 SVA 198 1% R
125 0.1% NA 11 UF 8.9 3.0 3.9 71.8 481.8 0.7 4.0 18 SVA 198 3% R
125 9.5 4.0 5.2 76.6 513.3 0.8 4.2 19 SVA 198 3% R 125 0.1% NA 11
UF 9.4 2.8 2.3 61.4 409.6 0.5 3.6 V1 K powder 50% talc A20 2.8 3.1
29.5 198.8 0.2 2.2 V2 D powder 965 9.6 20 D powder 0.1% NA 11 UF
678
__________________________________________________________________________
Fs = maximum force for penetrating the film in N Fs/D = maximum
force of the film for penetrating the film in relation to the cross
section in N/mm Wges/D = maximum damaging energy for penetrating
the film in J/mm Lges = maximum path for penetrating the film in
mm
* * * * *